In line with the overall thrust of this laboratory, to identify the principal variables of human temperature sensitivity and their neural correlates, the following topics of research are included in this application: 1. We propose to search the cortical projection area in SI of the hand of unanesthetized rhesus monkeys for single units that can be driven by skin temperature and temperature changes. The configurations of the stimuli will be such that responses of these units may be compared with behavioral measurements of the temperature sensitivity of the hand of rhesus monkeys and the psychophysical measurements of the hand of human subjects. The principal variables of the stimuli will be the temperature to which the skin has been adapted, the rate of temperature change, and the intensities of the temperature change. In addition, evidence of unilateral and bilateral spatial summation will be sought. 2. We propose to measure the return of tactile, thermal, and pain sensations to skin grafts in order to determine the pattern of the returning sensation, the time following grafting at which sensation returns, the best type of graft to ensure the return of sensation, and, as an ancillary aim, to develop a test battery that is clinically applicable to access cutaneous sensitivity.